The heart is the center of a person's circulatory system. It includes an electro-mechanical system performing two major pumping functions. The left portions of the heart, including the left atrium (LA) and left ventricle (LV), draw oxygenated blood from the lungs and pump it to the organs of the body to provide the organs with their metabolic needs for oxygen. The right portions of the heart, including the right atrium (RA) and right ventricle (RV), draw deoxygenated blood from the body organs and pump it to the lungs where the blood gets oxygenated. These pumping functions result from contractions of the myocardium (cardiac muscles). In a normal heart, the sinoatrial (SA) node, the heart's natural pacemaker, generates electrical pulses, called action potentials, that propagate through an electrical conduction system to various regions of the heart to excite the myocardial tissues of the cardiac muscles. For example, the action potentials originated from the SA node propagate through the atrioventricular (AV) node that is between RA and RV, the His bundle (also known as Bundle of His), and purkinje fibers to reach the ventricular myocardial tissues, resulting in contraction activities of the ventricles.
Coordinated delays in the propagations of the action potentials in a normal electrical conduction system cause the various portions of the heart to contract in synchrony to result in efficient pumping functions. A blocked or otherwise abnormal electrical conduction and/or deteriorated myocardial tissue cause dyssynchronous contraction of the heart, resulting in poor hemodynamic performance, including a diminished blood supply to the heart and the rest of the body. For example, an abnormal delay in the transmission of the action potentials in the His bundle can cause irregular or dyssynchronous contractions of the ventricles, resulting in an abnormal rhythm of the heart. In such events of cardiac malfunctioning, an artificial cardiac pacing system may be used. The artificial cardiac pacing system can provide electrical stimulations to one or more portions of the heart such as to restore normal functioning of the heart to a certain extent. However, the artificial cardiac pacing can result in dyssynchronous myocardial contraction patterns when not being used adequately. For example, His Bundle pacing may cause dyssynchronous myocardial contraction patterns when the electrical stimulation activates not only the His Bundle but also the adjacent myocardial tissue, an undesirable event referred to as non-selective His Bundle pacing. Therefore, there is a need for configuring cardiac pacing system for achieving the desirable therapeutic effects while reducing or eliminating unintended effects such as activation of non-targeted portions of the heart.